Battle of Hydaspes

The Battle of Hydaspes (326 BC) was the last battle of Alexander the Great, fought between his army of Macedon and the enemy army of Paurava under King Porus. Having subdued the Persian Empire, Alexander the Great proceeded to invade India, the only lands left unconquered by the Macedonian Empire. Although he faced overwhelming odds, Alexander destroyed Porus' Indian army of war elephants, chariots, cavalry, and infantry using flanking tactics.

Background
Following the Battle of Gaugamela, King Darius III of Persia fled to Ecbatana and then to Bactria, where he was killed by his own rebellious generals. Alexander the Great proceeded to subdue any remaining resistance to his conquest of the Persian Empire, and found another Persian army at the Persian Gates. His forces were held back, but a local shepherd showed him a way around the Persians. Alexander used this route, and he defeated the Persian army with a flanking attack. With little resistance, Alexander reached the Sogdian Rock and took over all of Bactria. The Persian Empire was now a part of Macedon, and there was nobody left to fight him.

Now that Persia was in his hands, Alexander was able to continue eastwards. Soon, dissent spread through his ranks, forcing him to stop at various points and turn in various directions before ultimately continuing east. He had each of his soldiers receive a Persian wife, and he murdered his general Parmenion after his son was accused of treason. With all of the dissenters dead, Alexander the Great continued on eastward. The Macedonian army crossed the Indus River into the Punjab, and Alexander captured the cities of Taxila and Aornos from the Indians, and allied with the Taxiles.

Alexander had little resistance as he advanced into the Punjab, but King Porus of Paurava gathered an army of 55,000 troops. King Porus' army counted 50,000 infantry, 4,000 cavalry, and 1,000 chariots, in addition to 85 fearsome Indian war elephants. Porus' army outnumbered Alexander's army four-to-one, and the two armies met on the Hydaspes River, the westernmost border of Paurava.

Dispositions
Alexander the Great's army of 13,000 troops included not only Macedonian troops from home, but it also included his new subjects. Persian Mardian Archers, Allied Cavalry, Bactrian auxillairies, and other troops from Persia made up a large portion of his army. The Macedonian army was positioned on the west bank of the Hydaspes. The Indian army of 55,000 troops was on the other side, but neither side wanted to go on the offensive first.

For three weeks, Alexander sent his cavalry up and down the banks of the river to the right of his army, and Porus responded by doing the same thing. Alexander located a ford on his left flank that he could use for outflanking the Indians, so he included that in his plan. Alexander positioned his main army close to the ford, while keeping two units of spearmen and a unit of archers on the center of the west bank and an army of equal size on the ford to the right. Porus' main force was in the center, with a large amount of reserves. He also had a smaller force on the side of the river facing the Macedonian right flank, but it was much larger than the force that the Macedonians fielded there.

Crossing of the Hydaspes
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